Issue #12213: Fix a buffering bug with interleaved reads and writes that
could appear on io.BufferedRandom streams.
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index c423dd6..608fc41 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -1367,15 +1367,18 @@
rw.seek(0, 0)
self.assertEqual(b"asdf", rw.read(4))
- rw.write(b"asdf")
+ rw.write(b"123f")
rw.seek(0, 0)
- self.assertEqual(b"asdfasdfl", rw.read())
+ self.assertEqual(b"asdf123fl", rw.read())
self.assertEqual(9, rw.tell())
rw.seek(-4, 2)
self.assertEqual(5, rw.tell())
rw.seek(2, 1)
self.assertEqual(7, rw.tell())
self.assertEqual(b"fl", rw.read(11))
+ rw.flush()
+ self.assertEqual(b"asdf123fl", raw.getvalue())
+
self.assertRaises(TypeError, rw.seek, 0.0)
def check_flush_and_read(self, read_func):
@@ -1520,6 +1523,44 @@
BufferedReaderTest.test_misbehaved_io(self)
BufferedWriterTest.test_misbehaved_io(self)
+ def test_interleaved_read_write(self):
+ # Test for issue #12213
+ with self.BytesIO(b'abcdefgh') as raw:
+ with self.tp(raw, 100) as f:
+ f.write(b"1")
+ self.assertEqual(f.read(1), b'b')
+ f.write(b'2')
+ self.assertEqual(f.read1(1), b'd')
+ f.write(b'3')
+ buf = bytearray(1)
+ f.readinto(buf)
+ self.assertEqual(buf, b'f')
+ f.write(b'4')
+ self.assertEqual(f.peek(1), b'h')
+ f.flush()
+ self.assertEqual(raw.getvalue(), b'1b2d3f4h')
+
+ with self.BytesIO(b'abc') as raw:
+ with self.tp(raw, 100) as f:
+ self.assertEqual(f.read(1), b'a')
+ f.write(b"2")
+ self.assertEqual(f.read(1), b'c')
+ f.flush()
+ self.assertEqual(raw.getvalue(), b'a2c')
+
+ def test_interleaved_readline_write(self):
+ with self.BytesIO(b'ab\ncdef\ng\n') as raw:
+ with self.tp(raw) as f:
+ f.write(b'1')
+ self.assertEqual(f.readline(), b'b\n')
+ f.write(b'2')
+ self.assertEqual(f.readline(), b'def\n')
+ f.write(b'3')
+ self.assertEqual(f.readline(), b'\n')
+ f.flush()
+ self.assertEqual(raw.getvalue(), b'1b\n2def\n3\n')
+
+
class CBufferedRandomTest(CBufferedReaderTest, CBufferedWriterTest, BufferedRandomTest):
tp = io.BufferedRandom